Gas lift flow device



Sept. 15, 1942. LED. MCWREY GAS LIFT FLOW .DEVICE Filed June 10, 1959 Lester D. M0wr y INVENTOR.

ATTORNEY.

Patented Sept.'1 5, 1942 NITE O FICE GAS LIFT FLOW DEVICE.

LesterD. Mowrey, Wichita Falls, Tex.

Application June 10, 1939, Serial No. 278,530

13 Claims.

The present invention relates to a method of and an apparatus for elevating liquids from a lower level to a higher level but morespeciflcally has for its purpose the lifting of water or oil in wells by air or gas pressure.

In all oil fields there is acertain quantity of gas associated with or dissolved in the oil when the reservoir is first penetrated. This gas functions to lift the oil while the well is on natural flow. After the well ceases to flow naturally, there is usually as much gas per barrel accompanying the oil from the formation as when the well was flowing naturally, but the reservoir pressure has declined until the gas is insufficient to continue the lifting operation. Under these 'circumstances it is necessary that some means be provided to lift the oil in the well.

Various types of gas-pressure liquid lifts have been employed, using both open and closed end floats; however, these have depended uponthe buoyancy of the floatto open a gas or air inlet valve so as to aerate the liquid to cause it torise within the tubing.

In the present invention the reverse principle is utilized, that is, as long as the float has a buoyancy greater than that of the displacement of the liquid, it will have a tendency to rise and close the valve. However, when this buoyancy decreases to the extent of being less than the buoyancy of the liquid displaced the float will sink, permitting the valve to introduce gas or air'into the tubing containing the liquid so as to aerate the liquid thereby causing it to move upward in the tubing.

As long as the liquid does not exert a hydrostatic pressure on the float to such an extent as to compress the air or gas within the float ,sothat the weight of the float is less than theweight of the liquid which it displaces, the float will hold the gas or air valve closed.

The apparatus comprising the present invention is entirely automatic in, operation, that is, when a hydrostatic head of a predetermined height accumulates within the tubing, the apparatus will function, thereby causing thegas or air inlet valve operated by the float to open and discharge a portion of gas or air into the liquid causing upward movement of the liquid through the tubing by the aerating medium thus introduced.

Less gaswill be wasted, in lifting the liquid by use of this invention than by the use of devices heretofore employed, because the float will permit the gas inlet valve to open only when a predetermined headof liquid is in the tubing, to ,be discharged.

It is therefore one object of the present invention to devise a method and apparatus for lifting liquids in wells whereby. the. natural gas and liquid pressure present therein ismade use of.

.Another object of the. present inventionis to provide .an improved float-controlled mechanism for operatinga valve, by which the valve will be operated by the lossin buoyancy of the float.

These and other objects will in part become obvious and in part be pointed out in the follow ing specification and appended claims when studied in conjunctionwith the attached drawing, in which:

Fig. 1 is a longitudinal sectional view through a well showing a plurality of flow units comprising the invention installed therein,

Fig. 2 is an enlarged longitudnal section of the upper. section of the flow unit and valve mechanism of the device,

Fig. 3 is an enlarged sectional View of the lower portion ofthe flow. unit, showing a check valve installedin the bottom thereof,

Fig. 4 is a horizontal section taken on the line 44 of the Fig.2 looking in the direction of the arrows,

Fig. 5 is a horizontalsection taken on the line 5.5 of the Fig. 2 looking in the direction of the arrows,

Fig. 6 is a horizontal section taken on the line 66 of the Fig. 3 looking inthe direction of the arrows.

In the drawing in which like numerals of reference indicate like parts, I refers to the ,Well casing of a conventional deep well having a casing head 2 at its upper end which casing head is "sealed bya cap 3'to prevent the escape of pressure from the well.

Within the well casing l is disposed a tubing 1 which extends to a point nearly to thefbottom of the well and has the, usual perforated pipe 5 mounted on the lower end thereof.

Flow units Bniay be mounted at spaced intervals in thetubingd, the number useddepending upon the depth and capacity of the ,'well.

The flow unit 6 comprises a float. chamber 1' and a reservoir 8 which gives an enlarged fluid capacity above the said floatchamber I. The reservoir 8 may vary in length from a few feet to several hundred feet depending upon the volnine of liquid to be handled by the device.

Interposed between the reservoir 8 and the chamber 1 is a coupling member 9 which has an inlet port I0 in the side thereof. .A valve H is operatively positioned to control the inlet of air or gas through the port l0 into the chamber 1 and reservoir 8.

For actuating the valve H an operating lever I2 is pivoted thereto at one end, andat its opposite end said lever is pivotally mounted at T4 in ,a dependent member l3 suspended from the cou- ,pling 9. The operating lever [2 has an arm I5 integrally attached thereto which'extends down ,wardly through the flow chamber 1' with itsfl ower .end. providedwith an offset foot portion in position to be engaged by a roller [6. The roller 1J5 mounted on the sides thereof. The float 2| comprises a cylindrical member closed at its upper end and open at the bottom thereof.

In operation, the upper portion of the enclosed well casing will be filled with entrapped gasunder pressure, and as the liquid rises through the perforated pipe 5 and the lower section of the tubing 4 and thence past the check valve 23 to thgggafichamber 1-,,the buoyancy of the liquid causes. the float 2| to rise and push the roller I6 against the off-set portion of the arm I 5, thereby causing the valve I I to close and prevent the gas or air from entering the tubing 4 through the port II]. The liquid will continue to rise within the tubing 4 and above the level of the float until the hydrostatic pressure compresses the air or gas within the upperend of the float 2I to such an extent that the displacement ofv the float A the float moves downwardly, the lever I2 will swing downwardly causing the valve II to open the port I I] and admit the air or gas under pressure to the chamber 1, aerating the oil contained therein, thereby causing a flow upwardly through the reservoir 8 and out through the tubing 4.

It is, of course, to be understood that the weight of the float assembly, without the entrapped gas, must be greater than the weight of the liquid which it displaces, and that the height of the column-of oil is dependent on the amount of pressure required to sink the float. These factors determine the points at which the valve opens and closes.

Air or gas may also be introduced from the outside at the upper end of the casing in order to furnish any additional pressure required. A supply pipe is indicated at in Fig. 1 of the drawing for the admission of such gas pressure to the casing, if desired.

By the use of the gas lift flow device comprising the present invention, the flowing pressure can be much lower than that used with ordinary gas lifts. By closing the casing at the top and holding the reservoir pressure within the casing, the reservoir pressure can be utilized for flowing after it has declined below the point where the well will flow naturally.

This pressure will elevate the liquid in the flow tubing to a point that is the reservoir limit lifting pressure. At this point the gas lift flow device may be installed to utilize the reservoir pressure to lift the liquid to the surface. If necessary a series of these devices may be installed as shown in the drawings accompanying the specification.

As the liquid becomes aerated it will move upwardly, and as the bubbles of gas within the liquid move upwardly, these bubbles will be under a less pressure, consequently they will expand to a greater size and the liquid will therefore move more freely through the tubing. The check valve 23 is held closed by a relatively weak spring which will permit the upward flow of liquid thereby, but upon the opening of the gas inlet valve, the valve 23 will be closed by the pressure thereon to prevent a downward surge of liquid which would cause agitation of the oil and foreign matter in the bottom of the well and might also drive this foreign matter into the pores of the producing formation.

When a series of flow units are installed, a hydrostatic head is built up above a second or additional flow unit and the same operation will occur as has just been described, each unit giving added aeration to the liquid.

A further advantage gained in using a float such as that described in the present specification is that this float will not collapse under pressure as the pressure is always equal inside and out at all points of the float.

It is to be noted that in the operation of the device, the casing or lift pressure has nothing .to do with the automatic control of the device as it is controlled by the hydrostatic pressure within the fluid discharge pipe, and therefore, the casing or lifting pressure can have a wide variance as it does not affect the operation of the said device.

From the foregoing description, taken in con nection with the accompanying drawing, it is thought the complete construction, operation and advantages of this invention will be clear to those skilled in the art to which it relates.

It is of course to be understood that the form of the invention, herewith shown and described, is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement'of the parts may be resorted to Without departing from the spirit of my invention, or the scope of the subjoined claims.

I claim:

1. In a device of the character described including a well casing, a flow tubing therein, said casing being closed about said tubing at its upper end, the combination of a flow unit in said tubing, an inlet port in said flow unit connecting the interior of said tubing with the casing, a valve for controlling said inlet port, and means for holding said valve closed until a predetermined pressure is applied to said means, said means comprising a float so constructed and arranged as to permit the opening of said valve as the buoyancy of the said float is decreased a predetermined amount by action of said predetermined pressure.

2. In a device of the character described including a well casing, a flow tubing therein, said casing being closed about said tubing at its upper end, means to introduce outside pressure into said casing, the combination of a flow unit in said tubing, an inlet port in said flow unit connecting the interior of said tubing with the exterior thereof, a valve controlling said inlet port, a float operatively connected with said valve, said float being closed at its upper end and open at the lower end thereof whereby a head of liquid may enter said float and cause it to hold said valve in closed position until gas contained in said float has been compressed sufficiently to cause the float to become less buoyant and drop, and a check valve mounted in said flow unit and below said float whereby after the operation of said float back flow downwardly through the flow tube isprevented.

3. In a fluid lift device for raising liquid from wells having a flow tube with an inlet opening, a control valve for the inlet opening for controlling the admission of pressure fluid to the flow tube, and means for holding said valve in a closed position, said means comprising a float so constructed and arranged as to permit operation of the valve at a predetermined loss in the buoyancy thereof, said float being spaced lengthwise of the flow tube from the inlet opening and valve and having said inlet opening and valve located wholly externally of the float, and means positioned below said float to prevent backward flow of the pressure liquid after operation of said float.

4. In a fluid lift device for raising liquid from wells having a flow tube with an inlet opening, a control valve for the inlet opening for controlling the admission of pressure fluid to the flow tube, a float operatively connected with said valve and adapted to hold the said valve in closed position, said float comprising a tube closed at its upper end and open at its lower end to allow entrance of a liquid head to entrap gas therein, and means for supporting said float from the flow tube comprising a lever arm pivotally supported by the flow tube and a link pivotally connected with said lever arm and the closed end of the float, said float being adapted to lose buoyancy as the pressure of the liquid head increases and compresses the gas therein and to permit said valve to open as the float drops at a predetermined pressure.

5. In a flew device, a chamber adapted for flow of liquid therethrough and having a gas inlet in a side thereof in position for admitting gas directly into said liquid, means for closing said gas inlet, and means movably mounted in the chamber and operatively connected with the inlet closing means, said movable means being constructed for trapping compressible fluid therein out of open communication with the gas inlet but in open communication with the liquid flow through the chamber and initially holding the gas inlet closed, said means moving in response to the compression of the fluid by the hydrostatic pressure of the liquid thereon to permit the opening of the gas inlet.

6. In a flow device, a chamber adapted for flow of liquid therethrough and having a gas inlet in a side thereof, a valve for controlling said gas inlet, and means in the chamber for actuating the valve, said means being movable by the liquid normally to hold the valve closed and having a compressible fluid therein, said means being constructed to entrap a compressible fluid therein and movable in response to a compression of the fluid by the liquid in the chamber for permitting opening of the valve.

7. In a flow device, a chamber adapted for flow of liquid therethrough and having a gas inlet in a side thereof, a valve for controlling said gas inlet, and float means in the chamber for actuating the valve, said gas inlet being arranged to admit fluid into the chamber externally of the float, said float means being movable by the liquid normally to hold the valve closed and having a compressible fluid trapped therein in communication with the chamber for compression by the hydrostatic pressure of the liquid, said float being movable to open the valve in response to the compression of the fluid.

8. In a flow device, a chamber adapted for flow of liquid therethrough and having a gas inlet in a side thereof, a valve for controlling said gas inlet, and float means in the chamber for actuating the valve, said float means being movable by the liquid normally to hold the valve closed and having a compressible fluid trapped therein in communication with the chamber for compression by the hydrostatic pressure of the liquid, said float means being movable in response to a compression of the fluid for permitting opening of the valve.

9. In a flow device, a chamber adapted for flow of liquid therethrough and having a gas inlet in a side thereof, a valve for controlling said gas inlet, and a float in said chamber operatively connected with said valve for actuating the same and in position for movement by the liquid in the chamber normally to hold the valve closed, said gas inlet being arranged to admit fluid into the chamber externally of the float, said float having a chamber therein with its upper portion closed and its lower portion in communication with the first-mentioned chamber in position to trap compressible fluid therein by the liquid, said float being constructed for movement in response to compression of the fluid by the hydrostatic pressure of the liquid to permit opening of the valve.

10. In a flow device, the combination of a casing, a flow tubing therein, means for confining gas under pressure in the casing around the tubing, a chamber in the casing connected with the tubing adapted for flow of liquid therethrough and having a gas inlet for admitting to the flow tubing said gas under pressure, means for controlling said gas inlet, and means movable in the chamber for actuating said controlling means, said movable means being constructed for trap ping compressible fluid therein for compression by the hydrostatic head of liquid in the chamber, said movable means being movable in response to a compression of the fluid for permitting opening of the inlet controlling means to admit gas to the flow tubing.

11. In a. flow device, the combination of a casing, flow tubing therein, means for confining gas under pressure in the casing around the tubing, a chamber in the casing connected with the tubing adapted for flow of liquid therethrough and having a gas inlet for admitting to the flow tubing said gas under pressure, means for controlling said gas inlet, and float means in the chamber for actuating said controlling means, said float means being constructed for trapping compressible fluid thereon in communication with the liquid in the chamber for compression by the hydrostatic head thereof, said float means being movable in response to a compression of the fluid for permitting opening of the inlet controlling means to admit gas to the flow tubing.

12. In a device for flowing a liquid from a well, the combination of flow tubing adapted to receive liquid therein, means for building up a gas pressure around the flow tubing, means for holding the gas pressure out of communication with the flow tubing by the pressure of the liquid therein, said means being constructed for movement in response to a gas compressing action in the flow tubing for admitting gas pressure thereto.

13. In a flow device, the combination of flow tubing adapted to be associated with gas under pressure for admission to the flow tubing, said flow tubing having a gas inlet, means for controlling said gas inlet, and means movable for actuating said controllingmeans, said movable means being constructed for trapping compressible fluid therein for compression by the hydrostatic head of liquid in the chamber and being movable in response to a compression of the fluid for permitting opening of the inlet controlling means to admit gas to the flow tubing.

LESTER D. MOWREY. 

